[0.73-stable] Add mouse hover events to RCTTextView

packages/react-native/Libraries/Text/Text/RCTTextShadowView.mm

@@ -84,7 +84,9 @@ - (void)uiManagerWillPerformMounting
                                                           exclusiveOwnership:YES];
 
   NSNumber *tag = self.reactTag;
-  NSMutableArray<NSNumber *> *descendantViewTags = [NSMutableArray new];
+  NSMutableSet<NSNumber *> *descendantViewTags = [NSMutableSet new]; // [macOS] avoids duplicates
+
+#if !TARGET_OS_OSX // [macOS]
   [textStorage enumerateAttribute:RCTBaseTextShadowViewEmbeddedShadowViewAttributeName
                           inRange:NSMakeRange(0, textStorage.length)
                           options:0
@@ -95,6 +97,22 @@ - (void)uiManagerWillPerformMounting
 
                          [descendantViewTags addObject:shadowView.reactTag];
                        }];
+#else // [macOS
+  [textStorage enumerateAttributesInRange:NSMakeRange(0, textStorage.length)
+                                  options:0
+                               usingBlock:^(NSDictionary<NSAttributedStringKey, id> *_Nonnull attrs, NSRange range, __unused BOOL * _Nonnull stop) {
+    id embeddedViewAttribute = attrs[RCTBaseTextShadowViewEmbeddedShadowViewAttributeName];
+    if ([embeddedViewAttribute isKindOfClass:[RCTShadowView class]]) {
+      RCTShadowView *embeddedShadowView = (RCTShadowView *)embeddedViewAttribute;
+      [descendantViewTags addObject:embeddedShadowView.reactTag];
+    }
+
+    id tagAttribute = attrs[RCTTextAttributesTagAttributeName];
+    if ([tagAttribute isKindOfClass:[NSNumber class]] && ![tagAttribute isEqualToNumber:tag]) {
+      [descendantViewTags addObject:tagAttribute];
+    }
+  }];
+#endif // macOS]
 
   [_bridge.uiManager addUIBlock:^(RCTUIManager *uiManager, NSDictionary<NSNumber *, RCTUIView *> *viewRegistry) { // [macOS]
     RCTTextView *textView = (RCTTextView *)viewRegistry[tag];
@@ -103,7 +121,7 @@ - (void)uiManagerWillPerformMounting
     }
 
     NSMutableArray<RCTPlatformView *> *descendantViews = [NSMutableArray arrayWithCapacity:descendantViewTags.count]; // [macOS]
-    [descendantViewTags
+    [[descendantViewTags allObjects] // [macOS] because it's an NSMutableSet now
         enumerateObjectsUsingBlock:^(NSNumber *_Nonnull descendantViewTag, NSUInteger index, BOOL *_Nonnull stop) {
           RCTPlatformView *descendantView = viewRegistry[descendantViewTag]; // [macOS]
           if (!descendantView) {

packages/react-native/Libraries/Text/Text/RCTTextView.mm

@@ -62,6 +62,7 @@ @implementation RCTTextView {
 
   id<RCTEventDispatcherProtocol> _eventDispatcher; // [macOS]
   NSArray<RCTUIView *> *_Nullable _descendantViews; // [macOS]
+  RCTUIView *_Nullable _currentHoveredSubview; // [macOS]
   NSTextStorage *_Nullable _textStorage;
   CGRect _contentFrame;
 }
@@ -99,6 +100,7 @@ - (instancetype)initWithFrame:(CGRect)frame
     _textView.layoutManager.usesFontLeading = NO;
     _textStorage = _textView.textStorage;
     [self addSubview:_textView];
+    _currentHoveredSubview = nil;
 #endif // macOS]
     RCTUIViewSetContentModeRedraw(self); // [macOS]
   }
@@ -414,6 +416,20 @@ - (void)handleLongPress:(UILongPressGestureRecognizer *)gesture
 }
 #else // [macOS
 
+- (BOOL)hasMouseHoverEvent
+{
+  if ([super hasMouseHoverEvent]) {
+    return YES;
+  }
+
+  // All descendant views of an RCTTextView are RCTVirtualTextViews
+  NSUInteger indexOfChildWithMouseHoverEvent = [_descendantViews indexOfObjectPassingTest:^BOOL(RCTUIView * _Nonnull childView, NSUInteger idx, BOOL * _Nonnull stop) {
+    *stop = [childView hasMouseHoverEvent];
+    return *stop;
+  }];
+  return indexOfChildWithMouseHoverEvent != NSNotFound;
+}
+
 - (NSView *)hitTest:(NSPoint)point
 {
   // We will forward mouse click events to the NSTextView ourselves to prevent NSTextView from swallowing events that may be handled in JS (e.g. long press).
@@ -428,6 +444,101 @@ - (NSView *)hitTest:(NSPoint)point
   return isTextViewClick ? self : hitView;
 }
 
+- (NSNumber *)reactTagAtMouseLocationFromEvent:(NSEvent *)event
+{
+  NSPoint locationInSelf = [self convertPoint:event.locationInWindow fromView:nil];
+  NSPoint locationInInnerTextView = [self convertPoint:locationInSelf toView:_textView]; // This is needed if the parent <Text> view has padding
+  return [self reactTagAtPoint:locationInInnerTextView];
+}
+
+- (void)mouseEntered:(NSEvent *)event
+{
+  // superclass invokes self.onMouseEnter, so do this first
+  [super mouseEntered:event];
+
+  [self updateHoveredSubviewWithEvent:event];
+}
+
+- (void)mouseExited:(NSEvent *)event
+{
+  [self updateHoveredSubviewWithEvent:event];
+
+  // superclass invokes self.onMouseLeave, so do this last
+  [super mouseExited:event];
+}
+
+- (void)mouseMoved:(NSEvent *)event
+{
+  [self updateHoveredSubviewWithEvent:event];
+
+  // As of the time of writing (2024-06-25), the latest versions of Safari, Firefox, Chrome, and Edge
+  // all run mousemove events from the innermost component outwards. While we don't have full support
+  // for mousemove events in react-native-macos yet, performing our internal updates before invoking
+  // the superclass is more aligned to this apparent Web behavior.
+  [super mouseMoved:event];
+}
+
+- (void)updateHoveredSubviewWithEvent:(NSEvent *)event
+{
+  RCTUIView *hoveredView = nil;
+
+  if ([event type] != NSEventTypeMouseExited && _descendantViews != nil) {
+    NSNumber *reactTagOfHoveredView = [self reactTagAtMouseLocationFromEvent:event];
+
+    if ([reactTagOfHoveredView isEqualToNumber:self.reactTag]) {
+      // We're hovering over the root Text element
+      hoveredView = self;
+    } else {
+      // Maybe we're hovering over a child Text element?
+      NSUInteger index = [_descendantViews indexOfObjectPassingTest:^BOOL(RCTUIView * _Nonnull view, NSUInteger idx, BOOL * _Nonnull stop) {
+        *stop = [[view reactTag] isEqualToNumber:reactTagOfHoveredView];
+        return *stop;
+      }];
+      if (index != NSNotFound) {
+        hoveredView = _descendantViews[index];
+      }
+    }
+  }
+
+  if (_currentHoveredSubview == hoveredView) {
+    return;
+  }
+
+  // self will always be an ancestor of any views we pass in here, so it serves as a good default option.
+  // Also, if we do set from/to nil, we have to call the relevant events on the entire subtree.
+  RCTPlatformView *commonAncestor = [(_currentHoveredSubview ?: self) ancestorSharedWithView:(hoveredView ?: self)] ?: self;
+
+  for (RCTPlatformView *exitedView = _currentHoveredSubview; exitedView != commonAncestor && exitedView != nil; exitedView = [exitedView superview]) {
+    if (![exitedView isKindOfClass:[RCTUIView class]]) {
+      RCTLogError(@"Unexpected view of type %@ found in hierarchy, must be RCTUIView or subclass", [exitedView class]);
+      continue;
+    }
+    RCTUIView *exitedReactView = (RCTUIView *)exitedView;
+    [self sendMouseEventWithBlock:[exitedReactView onMouseLeave]
+                     locationInfo:[self locationInfoFromEvent:event]
+                    modifierFlags:event.modifierFlags
+                   additionalData:nil];
+  }
+
+  // We cache these so we can call them from outermost to innermost
+  NSMutableArray<RCTUIView *> *enteredViewHierarchy = [NSMutableArray new];
+  for (RCTPlatformView *enteredView = hoveredView; enteredView != commonAncestor && enteredView != nil; enteredView = [enteredView superview]) {
+    if (![enteredView isKindOfClass:[RCTUIView class]]) {
+      RCTLogError(@"Unexpected view of type %@ found in hierarchy, must be RCTUIView or subclass", [enteredView class]);
+      continue;
+    }
+    [enteredViewHierarchy addObject:(RCTUIView *)enteredView];
+  }
+  for (NSInteger i = [enteredViewHierarchy count] - 1; i >= 0; i--) {
+    [self sendMouseEventWithBlock:[[enteredViewHierarchy objectAtIndex:i] onMouseEnter]
+                     locationInfo:[self locationInfoFromEvent:event]
+                    modifierFlags:event.modifierFlags
+                   additionalData:nil];
+  }
+
+  _currentHoveredSubview = hoveredView;
+}
+
 - (void)rightMouseDown:(NSEvent *)event
 {
 

packages/react-native/React/Base/RCTUIKit.h

@@ -406,6 +406,7 @@ CGPathRef UIBezierPathCreateCGPathRef(UIBezierPath *path);
 - (void)setNeedsDisplay;
 
 // Methods related to mouse events
+- (BOOL)hasMouseHoverEvent;
 - (NSDictionary*)locationInfoFromDraggingLocation:(NSPoint)locationInWindow;
 - (NSDictionary*)locationInfoFromEvent:(NSEvent*)event;
 

packages/react-native/React/Base/macOS/RCTUIKit.m

@@ -217,6 +217,7 @@ @implementation RCTUIView
   BOOL _clipsToBounds;
   BOOL _hasMouseOver;
   BOOL _userInteractionEnabled;
+  NSTrackingArea *_trackingArea;
   BOOL _mouseDownCanMoveWindow;
 }
 
@@ -349,6 +350,13 @@ - (void)viewBoundsChanged:(NSNotification*)__unused inNotif
   }
 }
 
+- (BOOL)hasMouseHoverEvent
+{
+  // This can be overridden by subclasses as needed.
+  // e.g., RCTTextView, which consolidates its JS children into a single gigantic NSAttributedString
+  return self.onMouseEnter || self.onMouseLeave;
+}
+
 - (NSDictionary*)locationInfoFromDraggingLocation:(NSPoint)locationInWindow
 {
   NSPoint locationInView = [self convertPoint:locationInWindow fromView:nil];
@@ -425,6 +433,28 @@ - (void)sendMouseEventWithBlock:(RCTDirectEventBlock)block
   block(body);
 }
 
+- (void)updateTrackingAreas
+{
+  BOOL hasMouseHoverEvent = [self hasMouseHoverEvent];
+  BOOL wouldRecreateIdenticalTrackingArea = hasMouseHoverEvent && _trackingArea && NSEqualRects(self.bounds, [_trackingArea rect]);
+
+  if (!wouldRecreateIdenticalTrackingArea) {
+    if (_trackingArea) {
+      [self removeTrackingArea:_trackingArea];
+    }
+
+    if (hasMouseHoverEvent) {
+      _trackingArea = [[NSTrackingArea alloc] initWithRect:self.bounds
+                                                   options:NSTrackingActiveAlways|NSTrackingMouseEnteredAndExited
+                                                     owner:self
+                                                  userInfo:nil];
+      [self addTrackingArea:_trackingArea];
+    }
+  }
+
+  [super updateTrackingAreas];
+}
+
 - (BOOL)mouseDownCanMoveWindow{
 	return _mouseDownCanMoveWindow;
 }

packages/react-native/React/Views/RCTView.m

@@ -136,7 +136,6 @@ @implementation RCTView {
   RCTUIColor *_backgroundColor; // [macOS]
   id<RCTEventDispatcherProtocol> _eventDispatcher; // [macOS]
 #if TARGET_OS_OSX // [macOS
-  NSTrackingArea *_trackingArea;
   BOOL _mouseDownCanMoveWindow;
 #endif // macOS]
   NSMutableDictionary<NSString *, NSDictionary *> *accessibilityActionsNameMap;
@@ -1466,28 +1465,6 @@ - (BOOL)acceptsFirstResponder
 	return [self focusable] || [super acceptsFirstResponder];
 }
 
-- (void)updateTrackingAreas
-{
-  BOOL hasMouseHoverEvent = self.onMouseEnter || self.onMouseLeave;
-  BOOL wouldRecreateIdenticalTrackingArea = hasMouseHoverEvent && _trackingArea && NSEqualRects(self.bounds, [_trackingArea rect]);
-
-  if (!wouldRecreateIdenticalTrackingArea) {
-    if (_trackingArea) {
-      [self removeTrackingArea:_trackingArea];
-    }
-
-    if (hasMouseHoverEvent) {
-      _trackingArea = [[NSTrackingArea alloc] initWithRect:self.bounds
-                                                   options:NSTrackingActiveAlways|NSTrackingMouseEnteredAndExited
-                                                     owner:self
-                                                  userInfo:nil];
-      [self addTrackingArea:_trackingArea];
-    }
-  }
-
-  [super updateTrackingAreas];
-}
-
 - (BOOL)mouseDownCanMoveWindow{
 	return _mouseDownCanMoveWindow;
 }